The influence of religious conservatives might be waning nationwide, but the movement only stands to grow in Congress.

Already this year, three candidates with close ties to massive churches won decisive Republican primaries. A fourth — Pastor Jody Hice — could win a Tuesday GOP primary runoff in Georgia and come to Congress in November.

Their victories come as public opinion has shifted dramatically on some social issues, notably same-sex marriage, denounced by most religious conservatives. The rise of the tea party and libertarian factions in the Republican Party has also diluted the influence of social conservative activists in the GOP.

But in the case of these faith-figures-turned-pols, the candidates' close relationships to their churches played a factor — perhaps the deciding one — in their victories.

"People generally like their pastor, and in politics it's always good to be liked by voters," said National Republican Congressional Committee Chairman Greg Walden of Oregon.

Lankford served as the director of youth programs at Falls Creek, one of the largest Baptist youth camps in the country that boasts bringing 55,000 people to Oklahoma's Arbuckle Mountains every summer. Republicans said that highly visible gig helped Lankford come out of nowhere to win his first House race in 2010 and defeat one of this cycle's most-talked about GOP Senate candidates in a June primary.

Until late last year, Baptist Pastor Mark Walker held a leadership role at Lawndale Baptist Church, which has a membership of a few thousand, in the heart of the 6th District in Greensboro, N.C. Last week, Walker defeated the well-connected son of one of North Carolina’s most powerful politicians by 6,300 votes in a GOP runoff .

Gary Palmer also won a Republican runoff last week, in Alabama’s 6th District race to succeed retiring Rep. Spencer Bachus. Palmer has close ties to Briarwood Presbyterian Church, one of the largest churches in Alabama with more than 4,000 members. The founding pastor has endorsed Palmer.

A fourth candidate, Hice, is locked in a competitive House runoff to succeed Rep. Paul Broun of Georgia, who lost a Senate primary in May. Hice's ties to a number of Baptist churches in the 10th District, including a faith-based talk radio show, could help him turn out his supporters in this district, located between the Atlanta exurbs and Augusta.

If Hice wins, he and Walker will raise the number of members of the clergy serving in Congress from six to eight.

The six faith leaders currently in the House include: Reps. Emanuel Cleaver II, D-Mo., a Methodist minister; Doug Collins, R-Ga., a Baptist pastor; Robert Pittenger, R-N.C., a former youth ministry organization manager for an Evangelical church; Juan C. Vargas, D-Calif., a Jesuit novice; and Tim Walberg, R-Mich., a former pastor.

Lankford, also one of the six, is on track to be the only former full-time religious leader in the Senate.

From a political perspective, operatives cite organizational abilities as a religious leader's No. 1 strength in campaigns. In low-turnout summer contests, that often leads to success.

“Churches do a good job of mobilizing and getting their people out because they’re organized, there’s phone trees, there’s a registry, and they certainly use that to get the word out,” said GOP ad maker Casey Phillips.

Republicans also remarked on the transferable skill set between clergy and politicians. For example, religious leaders are often expert empathizers after decades of counseling a congregation.

"Pastors and religious leaders of all faiths are there at the best times for the folks that they serve, and sometimes for the worst times," said Collins, a chaplain in the Air Force Reserves and a former senior pastor at Chicopee Baptist Church.

In 2012, Collins won an open-seat race in Georgia's 9th District. He said his background as a religious leader played a role in his victory.

"I have been there for births of children and I have been there to hold the hand of someone who took their last breath, and you deal with the families in between. That's what makes I think the faith perspective or the religious perspective I think a good thing in politics," Collins said. "If we wanted to 'survive' in our calling, you have to be compassionate, you have to listen. And we may not always agree, but I can agree or disagree in a way that leaves both of us in a position where we can understand each other."

But the reach of a megachurch's membership can only go so far.

In May, Mark Harris, a senior pastor at a megachurch in Charlotte, N.C., came in third in a Republican primary for Senate.

Harris was never able to raise the funds to compete with the eventual nominee, state Speaker Thom Tillis. Republican operatives in North Carolina also said Harris' church ties were diluted in a statewide race where 460,000 ballots were cast.

"It’s a bigger percentage of a congressional district than it is of the state," said Tom Perdue, a longtime Georgia operative who helped run Harris' campaign. "The smaller the population that you're running in when you have a base, the better off you are of having the potential to win."